Raster Time Series Animation

Downloading satelite imagery

Download the data from Sentinel Hub Playground.

library(dplyr)
library(lubridate)
library(stringr)
library(fs)
library(purrr)
library(glue)
library(magick)

Extract the dates from the filenames

dates <- tibble(file_paths = fs::dir_ls("data/2019-12-13-raster-time-series-animation_data/vir/", glob = "*.jpg")) %>%
  mutate(dates = as_date(str_extract(string = file_paths, pattern = regex(" [0-9]+-[0-9]+-[0-9]+"))))
dates

## # A tibble: 5 x 2
##   file_paths                                                          dates     
##   <fs::path>                                                          <date>    
## 1 data/2019-12-13-raster-time-series-animation_data/vir/Sentinel-2 L~ 2015-07-28
## 2 data/2019-12-13-raster-time-series-animation_data/vir/Sentinel-2 L~ 2016-07-02
## 3 data/2019-12-13-raster-time-series-animation_data/vir/Sentinel-2 L~ 2017-07-02
## 4 data/2019-12-13-raster-time-series-animation_data/vir/Sentinel-2 L~ 2018-07-07
## 5 data/2019-12-13-raster-time-series-animation_data/vir/Sentinel-2 L~ 2019-07-17

Make a gif out of the downloaded satelite imagery.

Import the files and create a gif utilizing “magick” for image processing.

Steps:

• List of filenames with dir_ls
• Read the images with image_read and join them image_join
• name the gif by using glue and dates$dates vector
• last step animate the gif at a frame rate of 0.5.

vir_gif <- dir_ls("data/2019-12-13-raster-time-series-animation_data/vir/", glob = "*.jpg") %>% 
    map(image_read) %>% 
    image_join() %>% 
    image_annotate(glue("Island of Vir:  {dates$dates}"), location = "+10+10", size = 20, color = "white") %>%
    image_animate(fps=0.5) %>% 
    image_write("data/2019-12-13-raster-time-series-animation_data/outputs/vir2015_2019.gif") 

Vir Croatia

Fornebu, Norway